U.S. patent number 4,679,755 [Application Number 06/741,408] was granted by the patent office on 1987-07-14 for support device for thin-walled tubing.
This patent grant is currently assigned to Stein Industrie. Invention is credited to Jean-Jacques Marsault, Jean-Pierre Peyrelongue, Jean-Claude Semedard, Gerard Vallee.
United States Patent |
4,679,755 |
Marsault , et al. |
July 14, 1987 |
Support device for thin-walled tubing
Abstract
A support or fixing device for pipework having walls which are
thin relative to its diameter and subjected to large temperature
variations and to radial forces. The device comprises: (a) support
cradles (2A, 2B, 2C, 2D) having an internal profile whose radius of
curvature is close to that of the pipework; (b) a rigid half-collar
(7) disposed around and spaced from the periphery of the pipework,
and having some of the cradles fixed thereto; (c) two arms (5A, 5B)
hinged at their ends to the half-collar and having others of the
cradles fixed thereto; and (d) a flexible arm clamping device (9)
resiliently applying the cradles against the pipework,
independently of expansions and radial forces applied to the
pipework.
Inventors: |
Marsault; Jean-Jacques (Saint
Arnoult en Yvelines, FR), Peyrelongue; Jean-Pierre
(Pontchartrain, FR), Semedard; Jean-Claude (Paris,
FR), Vallee; Gerard (Viroflay, FR) |
Assignee: |
Stein Industrie
(FR)
|
Family
ID: |
9304717 |
Appl.
No.: |
06/741,408 |
Filed: |
June 5, 1985 |
Foreign Application Priority Data
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Jun 5, 1984 [FR] |
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84 08788 |
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Current U.S.
Class: |
248/74.1; 24/19;
24/20S; 248/49; 248/65; 248/901 |
Current CPC
Class: |
F16L
3/16 (20130101); F16L 3/18 (20130101); F16L
59/135 (20130101); Y10T 24/1484 (20150115); Y10S
248/901 (20130101); Y10T 24/1412 (20150115) |
Current International
Class: |
F16L
59/12 (20060101); F16L 3/16 (20060101); F16L
3/18 (20060101); F16L 59/135 (20060101); F16L
003/08 () |
Field of
Search: |
;248/74.1,74.2,65,49,73,55,64,DIG.1,67.7 ;403/64,65,175 ;285/61
;24/19,205,285 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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482629 |
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Dec 1925 |
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DE2 |
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3001028 |
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Jul 1981 |
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DE |
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Primary Examiner: Ramirez; Ramon O.
Attorney, Agent or Firm: Sughrue, Mion, Zinn, Macpeak, and
Seas
Claims
We claim:
1. A fixing device for a pipework (1) having a cylindrical wall
which is thin relative to its diameter and subjected to large
temperature variations and to radial forces in arbitrary
directions, said device comprising:
a. sectional support cradles (2A, 2B, 2C, 2D) having pipework
contacting faces;
b. a rigid half-collar (7) for disposal around the periphery of the
pipework, and having some of the cradles mounted thereto;
c. two arms (5A, 5B) hinged at their ends to respective ends of the
half-collar and having others of the cradles mounted thereto;
and
d. a flexible arm clamping device (9) resiliently mounted to said
two arms for drawing said arms together to apply the cradles
against the pipework, independently of expansions and radial forces
applied to the pipework.
2. A device according to claim 1, further comprising a layer of
material which is heat-resistant and capable of elastic crushing
covering the cradles on their pipework contacting faces.
3. A device according to claim 2, wherein said material is a
compressed knit of a fine metal wire.
4. A device according to claim 1, wherein said cradles are
respectively pivoted (3A, 3B, 4A, 4B) to the rigid half-collar (7)
and to the hinged arms (5A, 5B).
5. A device according to claim 1, wherein said arms include major
portions pivoted to said half-collar and said device further
comprises thermal lagging (13) for surrounding the pipework, the
cradles and the half-collar, and the major portions of the hinged
arms are disposed inside said thermal lagging and the flexible
clamping device is disposed outside said lagging.
6. A device according to claim 1, wherein the rigid half-collar is
connected via dual links (11A, 11B) to respective means (12A, 12B)
for preventing rapid radial shifting of said rigid half-collar
while providing slow radial shifting of said rigid half-collar for
locking said half-collar automatically in the event of rapid
displacement, but allowing slow displacement of said rigid
half-collar relative to said pipework by forces transmitted from
said pipework to said rigid half-collar.
Description
The present invention relates to a support device for tubing having
a wall thickness which is thin relative to its diameter, and
subjected to large temperature variations and to radial forces in
arbitrary directions.
BACKGROUND OF THE INVENTION
The Applicant has already proposed devices of this kind in
published French patent specifications Nos. 2 443 001 and 2 499
202, which devices are suitable for supporting or fixing the
pipework which transports liquid sodium in breeder reactor power
stations, and which withstands seismic shocks. These devices
include force pickup members welded to the pipework and constituted
by circular pegs which engage in holes in resilient blades which
are welded at least at one of their ends to radial bars which are
fixed to a rigid collar surrounding the pipework. This requires a
relatively high number of welds, such that installation is lengthy
and expensive.
The aim of the present invention is to provide a support device for
tubing whose walls are thin relative to the tubing diamter, which
holds the tubing without play and without applying excessive
stresses thereto, regardless of the diametral expansions and forces
applied, without requiring force take-up devices welded to the
pipework, which is easily and rapidly put into place, which enables
the pipework to be lagged against heat losses even where the
support is disposed, and which allows the degree to which the
pipework is clamped to be adjusted.
SUMMARY OF THE INVENTION
A device according to the invention is characterized in that it
comprises:
a/ support cradles having an internal profile with a radius of
curvature close to that of the pipework;
b/ a rigid half-collar disposed around and spaced from the
periphery of the pipework and on which some of the cradles are
fixed;
c/ two arms hinged to the ends of the half-collar and having the
other cradles fixed thereto; and
d/ a flexible arm clamping device resiliently applying the cradles
against the pipework, independently of diametral expansions and
radial forces applied to the pipework.
The support preferably includes at least one of the following
characteristics:
the radius of curvature of the internal profile of the cradles is
slightly greater than the radius of curvature of the pipework when
cold;
the cradles are covered on their pipework-contacting faces in a
layer of material which is heat-resistant and which is capable of
being crushed elastically;
the material capable of being crushed elastically is a compressed
knit of fine metal wire;
the cradles are pivotably fixed to the rigid half-collar and to the
hinged arms;
the cradles, the half-collar and the major portion of the hinged
arms are disposed inside thermal lagging surrounding the pipework,
and the flexible clamping device is disposed outside said thermal
lagging; and
the rigid half-collar is connected via links to static support
members or to members which lock automatically in the event of fast
displacement, but which allow slow displacements to take place.
There follows a description by way of example with reference to the
sole figure of the accompanying drawing which shows a support
device for pipework for transporting molten metal, such as sodium,
in an electricity power station having a breeder reactor. It is
known that the temperature of such pipework can vary very rapidly,
by 100.degree. or 200.degree. C. in a few minutes.
BRIEF DESCRIPTION OF THE DRAWING
The FIGURE shows the device in diametral sections (on a right
cross-section of the pipework).
DESCRIPTION OF THE PREFERRED EMBODIMENT
The large diameter pipework 1 has a diameter of about 700 mm to
1000 mm, and has thin walls which are 10 mm to 20 mm thick. It is
clamped between four cradles 2A, 2B, 2C and 2D which are regularly
distributed around its periphery, and which have a radius of
curvature which is slightly greater than the radius of curvature of
the pipework when cold and which may be equal to the maximum radius
of the pipework when hot. The lower cradles 2A and 2B are fixed via
pivots 3A and 3B to a rigid half-collar 7. The other two cradles 2C
and 2D are fixed via pivots 4A and 4B to two arms 5A and 5B which
are hinged at 6A and 6B to the rigid half-collar 7. All of the
cradles are covered on their pipework-facing faces, in a layer 8 of
material which is heat-resistant and which is capable of elastic
crushing, such as a compressed knit of fine stainless steel wire
which withstands 500.degree. C. while retaining its properties.
Spring members 10A, 10B urge the hinged arms towards each other and
serve to apply the cradles 2C and 2D against the pipework with a
determined force.
Links 11A and 11B fixed to the rigid half-collar 7 serve to fasten
said collar to self-locking devices 12A and 12B which may be
hydraulic or mechanical.
The pipework is surrounded by heat insulating lagging 13 in which
the cradles, the half-collar, and the major portion of the arms 5A
and 5B are received, leaving only the clamping member 9 outside the
lagging.
It can be seen that if the clamping springs 10A and 10B are
suitably rated, forces are rapidly transmitted between the pipework
1 and the self-locking devices 12A and 12B, which constitute
snubbers preventing radial shifting of the rigid half-collar 7
while providing slow radial shifting of the rigid half-collar
whereby the snubbers lock in the event of fast radial displacement,
but which allow slow displacements to take place. If the pipework
expands or contracts radially due to a change in the temperature of
the liquid metal flowing therethrough, the pipework continues to be
held rigidly and without play, while remaining protected from
excessive clamping due to the resilience of the springs.
The freedom of the cradles 2A and 2B to pivot about the pivots 3A
and 3B enables centered contact to be retained between the pipework
and the cradles regardless of the alterations in pipework shape and
the small thermal deformations which may occur in the half-collar
7. In addition, by placing the four cradles at 90.degree. to one
another, any tendency of the pipework to become oval under the
clamping force is compensated.
Although the device which has just been described with reference to
the figure in the drawing appears to be the preferred embodiment of
the invention, it will be understood that various modifications may
be made thereof without going beyond the scope of the invention,
with various members being replaceable by others which perform an
analogous technical function. In particular, the number of cradles
may be modified, with the minimum number being two. The half-collar
could occupy a fraction of the peripheray of the pipework which is
greater than or less than 180.degree.. The number of hinged arms
could be greater than two, and could even be an odd number. The
clamping springs could be replaced by spring washers of the
"Belleville" type.
* * * * *